Bird Dog

How to do it

Start on your hands and knees: hands directly under your shoulders, knees under your hips, spine neutral. Reach one arm forward and the opposite leg back until both are parallel to the floor. Reach long, not high — going high arches your lower back. Return with control before switching sides.

Why it's good for runners

Your core has to keep you from twisting while one arm and one leg move — that's exactly what it does when you run, with your arm and opposite leg swinging through every stride. A simple drill that targets the exact pattern you use thousands of times per run.

Common mistakes

Keep your hips and shoulders level the whole time. Most people drop one hip when the leg goes up — if you can't stay level, lift only the arm or only the leg until your stability catches up.